1. Field of the Invention
The present invention generally relates to thin film sensor technology, and more particularly, relates to thin film sensor technology for measuring breathing air flow.
2. Description of the Prior Art
It is known in the art to employ respiration sensors to monitor patients susceptible to sleep apnea and other disorders of the respiration system. U.S. Pat. No. 4,878,502 issued to Dietz discusses a breathing sensor employing a tubular passage in which a ball is free to move to break a beam of light. The ball is moved in response to the flow of air associated with the breathing of the patient. An optoelectric inhalation sensor using thin film deposition is discussed in U.S. Pat. No. 4,745,925 issued to Dietz.
Acoustic sensors for monitoring respiration are mentioned in U.S. Pat. No. 4,602,644 issued to DeBenedetto et al., and in U.S. Pat. No. 4,595,016 issued to Fertig et al. U.S. Pat. No. 4,366,821 issued to Wittmaier et al., shows a respiration monitoring system which preferably uses a gas sensor, and U.S. Pat. No. 4,350,166 issued to Mobarry shows a video monitor. Moisture is sensed using a sodium chloride crystal in U.S. Pat. No. 4,326,404 issued to Mehta.
U.S. Pat. No. 4,306,867 issued to Krasner shows the use of a pressure sensor. An impedance plethysmograph is employed in U.S. Pat. No. 4,289,142 issued to Kearns. The use of thermoresistive sensors is suggested in U.S. Pat. No. 3,903,876 issued to Harris, U.S. Pat. No. 3,884,219 issued to Richardson et al., and U.S. Pat. No. 3,999,537 issued to Noiles.